Design/Architecture question

ONLINE SESSION BASED FORM FILLING WEB SERVICE Goal: To create a session based online form filling web service. Example: Say I want to fill a Tax form. The user should just enter his email, fill the online form, and get a pdf in mail, which looks exactly like a government form, but filled, with the user’s data. There will no user’s data stored in the server. It will be session based. This project is for a best design/Architecture suggestion, to accomplish this. I have attached my thoughts. I need your design / architecture justification of the best way to approach this. The current project is only for design/architecture recommendation. I will select one that I find is the best.